x86, mm: pass in 'total' to __copy_from_user_*nocache()

Impact: cleanup, enable future change

Add a 'total bytes copied' parameter to __copy_from_user_*nocache(),
and update all the callsites.

The parameter is not used yet - architecture code can use it to
more intelligently decide whether the copy should be cached or
non-temporal.

Cc: Salman Qazi <sqazi@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/include/asm/uaccess_32.h

@@ -157,7 +157,7 @@ __copy_from_user(void *to, const void __user *from, unsigned long n)
 }
 
 static __always_inline unsigned long __copy_from_user_nocache(void *to,
-				const void __user *from, unsigned long n)
+		const void __user *from, unsigned long n, unsigned long total)
 {
 	might_fault();
 	if (__builtin_constant_p(n)) {
@@ -180,7 +180,7 @@ static __always_inline unsigned long __copy_from_user_nocache(void *to,
 
 static __always_inline unsigned long
 __copy_from_user_inatomic_nocache(void *to, const void __user *from,
-				  unsigned long n)
+				  unsigned long n, unsigned long total)
 {
        return __copy_from_user_ll_nocache_nozero(to, from, n);
 }

arch/x86/include/asm/uaccess_64.h

@@ -189,7 +189,7 @@ extern long __copy_user_nocache(void *dst, const void __user *src,
 				unsigned size, int zerorest);
 
 static inline int __copy_from_user_nocache(void *dst, const void __user *src,
-					   unsigned size)
+				   unsigned size, unsigned long total)
 {
 	might_sleep();
 	/*
@@ -205,8 +205,7 @@ static inline int __copy_from_user_nocache(void *dst, const void __user *src,
 }
 
 static inline int __copy_from_user_inatomic_nocache(void *dst,
-						    const void __user *src,
+	    const void __user *src, unsigned size, unsigned total)
-						    unsigned size)
 {
 	if (likely(size >= PAGE_SIZE))
 		return __copy_user_nocache(dst, src, size, 0);

drivers/gpu/drm/i915/i915_gem.c

@@ -215,7 +215,7 @@ fast_user_write(struct io_mapping *mapping,
 
 	vaddr_atomic = io_mapping_map_atomic_wc(mapping, page_base);
 	unwritten = __copy_from_user_inatomic_nocache(vaddr_atomic + page_offset,
-						      user_data, length);
+						      user_data, length, length);
 	io_mapping_unmap_atomic(vaddr_atomic);
 	if (unwritten)
 		return -EFAULT;

include/linux/uaccess.h

@@ -41,13 +41,13 @@ static inline void pagefault_enable(void)
 #ifndef ARCH_HAS_NOCACHE_UACCESS
 
 static inline unsigned long __copy_from_user_inatomic_nocache(void *to,
-				const void __user *from, unsigned long n)
+		const void __user *from, unsigned long n, unsigned long total)
 {
 	return __copy_from_user_inatomic(to, from, n);
 }
 
 static inline unsigned long __copy_from_user_nocache(void *to,
-				const void __user *from, unsigned long n)
+		const void __user *from, unsigned long n, unsigned long total)
 {
 	return __copy_from_user(to, from, n);
 }

mm/filemap.c

@@ -1816,14 +1816,14 @@ EXPORT_SYMBOL(file_remove_suid);
 static size_t __iovec_copy_from_user_inatomic(char *vaddr,
 			const struct iovec *iov, size_t base, size_t bytes)
 {
-	size_t copied = 0, left = 0;
+	size_t copied = 0, left = 0, total = bytes;
 
 	while (bytes) {
 		char __user *buf = iov->iov_base + base;
 		int copy = min(bytes, iov->iov_len - base);
 
 		base = 0;
-		left = __copy_from_user_inatomic_nocache(vaddr, buf, copy);
+		left = __copy_from_user_inatomic_nocache(vaddr, buf, copy, total);
 		copied += copy;
 		bytes -= copy;
 		vaddr += copy;
@@ -1851,8 +1851,9 @@ size_t iov_iter_copy_from_user_atomic(struct page *page,
 	if (likely(i->nr_segs == 1)) {
 		int left;
 		char __user *buf = i->iov->iov_base + i->iov_offset;
+
 		left = __copy_from_user_inatomic_nocache(kaddr + offset,
-							buf, bytes);
+							buf, bytes, bytes);
 		copied = bytes - left;
 	} else {
 		copied = __iovec_copy_from_user_inatomic(kaddr + offset,
@@ -1880,7 +1881,8 @@ size_t iov_iter_copy_from_user(struct page *page,
 	if (likely(i->nr_segs == 1)) {
 		int left;
 		char __user *buf = i->iov->iov_base + i->iov_offset;
-		left = __copy_from_user_nocache(kaddr + offset, buf, bytes);
+
+		left = __copy_from_user_nocache(kaddr + offset, buf, bytes, bytes);
 		copied = bytes - left;
 	} else {
 		copied = __iovec_copy_from_user_inatomic(kaddr + offset,

mm/filemap_xip.c

@@ -354,7 +354,7 @@ __xip_file_write(struct file *filp, const char __user *buf,
 			break;
 
 		copied = bytes -
-			__copy_from_user_nocache(xip_mem + offset, buf, bytes);
+			__copy_from_user_nocache(xip_mem + offset, buf, bytes, bytes);
 
 		if (likely(copied > 0)) {
 			status = copied;